Electric control instrument



E. N. JACOB! ELECTRIC CONTROL INSTRUMENT Original Filed March 11, 1943Jan. 23, 1951 3 Sheets-Sheet 1 Jmkwd E WETDJXZI Jacubz g 0)? Jan. 23,1951 E. N. JACOB] 2,539,252

ELECTRIC CONTROL INSTRUMENT Original Filed March 11, 1943 5 Sheets-Sheet2 l lw" a (IMAM,

Jan. 23, 1951 E. N. JACOB] ELECTRIC CONTROL INSTRUMENT Original FiledMarch 11, 1943 s sheet 5 Patented Jan. '23, 1 951 2,539,252 ELECTRICCONTROL INSTRUMENT Edward N. Jacobi, Milwaukee, Wis., assignor to Briggs& Stratton Corporation, Milwaukee, Wis., a corporation of Delaware 1Original application March 11, 1943, Serial No.

478,763, now Patent No. 2,450,144, dated September 28, 1948. Divided andthis application December 29, 1947, Serial No. 794,244

This invention relates to electrical control instrumentalities andrefers more particularly to master switches for aircraft.

In aircraft it is customary to provide a separate switch for each engineto control the two magnetos with which the engine is provided forignition purposes. switches provided for each of the electricalinstrumentalities on the aircraft, it is also customary to provide asingle readily accessible master switch whereby in an emergency all ofthe electrical circuits in the aircraft can be broken and all of theengines simultaneously cut off by actuation of a single switch lever.The so-called master switch by means of which this operation is effectedis commonly associated with the switch or switches which controlgrounding of the individual engine magnetos, and it must be so designedthat it will make grounding circuits for all magnetos at the same timethat it breaks the electrical power supply circuits, and vice versa.

This invention relates to a switch of the master control type which isparticularly adapted for use with a pair of magneto control switches andis especially well suited for use in conjunction with the switchdescribed in my copending application, Serial No. 478,763, filed March11, 1943, now Patent No. 2,450,144, September 28, 1948, of which thisapplication is a division.

It is thus an object of this invention to provide a master switch of thecharacter describedhaving a novel one-piece lever providing both acarrier'for a multiplicity of movable contacts and an actuator forswingin the carrier to and from positions at which it contacts engagecooperating stationary contacts.

Another object of this invention resides in the provision of a novelmanner of associating the movable contacts as a unit with the lever ofthe master switch to thereby simplify assembly of the switch.

"With the above and other objects in view, which will appear as thedescription proceeds, this in-- vention resides in the novelconstruction, combination and arrangement of parts substantially ashereinafter described and more particularly defined by the appendedclaims, it being understood that such changes in the precise embodimentof the herein disclosed invention may be made as come within the scopeof the claims.

The accompanying drawingsillustrate one complete example of the physicalembodiment of the invention constructed according to the best mode: sofar devised for the practical application of the principles thereof, andin which:

In addition to the usual 15 Claims. (01. 200-7) Figure 1 is anelevational view of a typical switch assembly incorporating the masterswitch of this invention;

1 Figure 2 is a left side view of the master switch l of thisinvention,"a portion of a magneto control switch being indicatedtherebeneath;

FigureB is a rear elevational view of the switch assembly'shown inFigure V Figure 4 is a view similar to Figure 2 but showing the interiorof the switch;

Figure 5 is a sectional view taken through Figure 4 on the plane of theline 55;

Figure 6 is a perspective view of theswitch lever illustrating themanner in which the movable contacts carried thereby are assembled withthelever. as a unit;

Figure '7 is a detail sectional view taken, through Figure 4 on theplanev of the line l'|;' Figure 8 is a perspective view of themasterswitch housing showin one of the terminal heads separatedtherefrom;

Figure 9 is a perspective view illustrating the construction of thebattery circuit contactor of.

the master switch; and Figure 10 is an exploded perspective view of thecomponents of the guideway for the battery cir-' cuit contactor.Referring now more particularly to the accompanying drawings in whichlike numerals designate like parts throughout the several views, thenumeral 20 designates a switch assembly having.

a pair of individual magneto switches 2| and 22 and a master switch 23.

Since each magneto grounding switch controls, two magnetos and a magnetobooster, and since each switch has three positions of operativeness,

designated L, R, and Both in Figure 1, it follows that either of the twomagnetos controlled by each switch may be rendered opera-,

tive or inoperative as desired, or that both may be rendered effective.In the off position of the switches the magnetos and their boosters areall rendered ineiiective.

The master switch.23 is secured to a panel 24 centrally and above thetwo magneto grounding switches 2|, and 22,. and is operated by means ofva readily accessible lever 21, located between, and

directly above, the magneto switch handles 25.

The master switch 23 is enclosed within a housing '66 formed jointly bya band of brass ll bent to substantially U-shape (see Fig. 8) and a pairof substantially rectangular insulating sheets 18 secured flatwiseagainst the opposite side edges,

of the band so as to provide spaced apart sub-v stantially parallelterminal headsfor the switch.

Opposite lugs 19 bent outwardly from the extremity of the upper leg ofthe band I! cooperate with a lu 8i] bent downwardly from the extremityof the lower leg of the band to mount the housing from the panel 24-with the open side of the housing facing the rear of the panel andclosed thereby.

The two corners of the terminal heads remote from the panel 24 areriveted as at 8I to ears 82 bent outwardly from the band 'I'I, while theupper corner of each terminal head adjacent to the panel 24 is rivetedas at .83 to cars 83 bent inwardly from the edges of the band 11.

Spaced apart substantially parallel lugs 84 bent inwardly from theopposite edges of the metal band TI provide for securement of the fourthcorner of each terminal head 'to the band and for pivotally mounting theoperating lever 21 of the master switch.

The operating lever is medially pivotally mounted on a pin 85 (seeFigure '2) and the opposite ends of this pin are received in alignedholes in the lugs or standards 84. The opposite ends of the pin 85' alsoproject through holes in the terminal heads and have rivet heads formedthereon so that the pin which pivotally mounts the lever also providesfor securing together the fourth corner of the switch housing.

The inner end 86 of the lever projects into the housing for swingingmotion across the opposing faces of the terminal heads and constitutes acontact carrier. For this purpose it is provided with a pair of holes orrecesses '81 and 88 spaced different radial distances from the pivotaxis.

Identical spider-like brass -.contact members 9| have depressed medialportions 92 overlying the hole 88 at opposite sides of the lever and arejoined by a rivet 93 which passes through the hole 88 and'the heads ofwhich limit diverging motion of the contact members. Each of the contactmembers :has three arms extending radially outwardly from its medialportion to overlie the adjacent face or the carrier '88 and theextremities of these arms have hollow .convex=contact portions 9 3, 95'and .96 engaging the opposing faces of the terminal heads.

The contact members 91 are yieldingly urged apart and into engagementwith the inner faces of the terminal heads adjacent thereto by a spring!in the hole 88 .(see Figure In addition, contact pressure for theindividual contacts 94, 95 and 96 is aiiord'ed'iby meanssof compressionsprings 93 passing through suitable holes 99 in the carrier and havingtheir opposite ends received inside the hollow socket-like interiors ofthe contact portions.

As will be clearly understood from Figure 5, the heads of the rivet 93do not interfere with yielding engagement of the contacts 94, 95 and 96with the inner faces of the terminal heads, but prior to mounting of thelever in the housing, the rivet 93 acts to hold the contact membersassembled with the lever.

Movement of the contact members '9'I either about the axis of therivet93 or out of coaxiality with respect to the hole '88 is precludedby lugs I00 projecting from opposite faces of the carrier and engagingvarious edge portions of the contact members.

A resilient brass grounding connector IilI for each of the contactmembers 91 has an integral eyelet I02 at one end encircling :thedepressed medial portion 92 of its contact member and confined betweenthe adjacent endof the spring 4 91 and the contact member, and anotherintegral eyelet I03 at its other end lying alongside the face of the hubof the lever so as to be disposed between the hub of the lever and thelug or standard. adjacent thereto.

A compression spring 104 received in an annular recess I95 in the leverconcentric with its hub yieldingly presses the eyelet 803 of one of thegrounding connectors into engagement with the adjacent lug or standard84.

Thus since the attaching ear of the housing is electrically joined witha ground terminal 58 on one of the magneto control switches by means ofa brass connector I06, it follows that the movable contacts 94, and 96are at all times grounded through an all brass circuit. This isdesirable because it eliminates the possibility of electrolytic actionwhich may occur when electrical circuits are led through dissimilarmetals.

Stationary contacts 1101, I08 and I69, carried by each terminal head l8and engaged by the movable contacts 94, 95 and 96 in the off position ofthe master switch, shown in Figure 4, ground all of the magnetos. Forthis purpose the stationary contacts Ill-I, I98 and Illa-on eachterminal head havecorresponding normally 'ungrounded terminals I91, I08and H39 exteriorly of the housing electrically connected with thenormally ungroundcd terminals E2, 64 and 69 of one magneto groundingswitch by short fiexible'conductors as shown in Figure 3.

Consequently, simultaneous engagement of the I six grounded movablecontacts 94, 95 and 96 with their cooperating stationary contacts on theterminal heads by actuation of the lever 21 to the oil position of theswitch simultaneously connects the normally ungrounded terminals of thefour magnetos controlled by the two magneto grounding switches 2| and2.2 with the ground, regardless of the positions of theindividualmagneto switches.

In addition to the stationary contacts previously described, each of theterminal heads 13 has an additional stationary contact IIil exposed onits inner face and connected with a corresponding :battery terminal III!on the exterior contacts IIO simultaneously to disrupt all of' the Uponactuation of the lever 21- battery circuits. to the on positionof theswitch, .in which all of the magnetos are under the direct control of"the two magneto grounding switches, the bridging contactor contacts Hi9to enable the-various electrically operated instrumentalities of thecraft to be connected with their source of E. M. F. through theirindividual switches.

The bridging contactor H! is of special construction to permit itsassembly withthe carrier 86 as aunit, andto this end the contactor com-'prises a pair of opposite hollow telescoping plungers II2, substantiallyrectangular in cross section as shown in Figure *9, which enter the hole81 in the carrier 86 from opposite faces of 75 the carrier. Theseplungersareguided foraxial III engages the two stationary.

the jumper motion inthe hole 81 by an insulating guideway H3 serving asa lining for the hole 81. The end portions of the plungers facing theterminal heads 78 are formed with a convex shape, as shown, so as toengagejheconcave faces of the stationary contacts HQ ,with a detentaction under the influence of a compression spring H4 confined betweenthe plungers to yieldingly urge the same apart.

A tang. H5 on each of the plungers engages a cooperating shoulder H6 oneach side of the insulating guideway to limit spreading apart of theplungers in response to pressure of the spring between them to enablethe bridging contactor to be assembled with the carrier 86 prior toassembly of the lever with the housing.-

Although the spring H4 is capable of electricallyconnecting the plungersI I2, it is not relied upon in the present instance other than to pressthe ends of a flexible braided jumper HI looped about the coils of thespring into firm engagement with the contact engaging ends of theplungers. Thus, since the spring is shunted out of the electricalcircuit between the plungers by II'I, the jumper provides an electricalconnection between the plungers H2 which insures maximum andundiminished current carrying capacity therebetween.

The rectangular shape of. the telescoping plungers precludes rotation ofthe same relative to each other about the axis of the hole 81, and inaddition provides corner spaces inside the plungers alongside thecompression spring I I4 to accommodate two stretches of the braidedjumper I I1.

Attention is directed to the fact that the insulating guideway H3 forthe plungers of the bridging oontactor is formed of four separate piecesinterlocked together and secured in the hole'8'I in a novel manner.Referring to Figures 6 and 10, it will be seen that the hole 8'! issubstantially rectangular and that the guideway comprises identical topand bottom plates I I8 and H9, respectively, retained in spaced apartparallel relationship by similar upright side plates I26 and I2I andcooperating with them to form a hollow rectangular unit fitting the hole81.

The top and bottom plates have a depth greater than the thickness of thecarrier 86 so as to project from opposite faces thereof and so thatlaterally extending shoulders I 22, formed by notches I23 cut into theopposite side edges of these plates, overlie the opposite faces o'f'thecarrier 85 alongside the hole 8?. The notches I23 also serve to receivetabs I24 on the top and bottom edges of the side plates so that the topandbottom plates H8 and II 9 hold the side plates spaced apart andparallel and secure them against motion relative to the carrier axiallyof the hole 61. I

The carrier 86 is provided with a slot I25 leading to the hole 81 butnarrower than the hole to provide for assembly of the insulatingguideway in the hole. In assembly, the bottom plate I I9 is firstinserted into the hole through the slot I25 to its proper position shownin Figure 6; The side plates I20 and *I2I are next inserted so thattheir lower tabs engage in the notches I23 of the bottom plate, and thetop plate is then slipped into its proper position shown in Figure 6with the upper tabs of the side plates received in its notches I23.

Attention is directed to the fact that the side plates are oi suchheight that clearance is provided between overhanging ledges I26 on thecarrier at opposite sides of the entrance to the hole and the top plate.This clearance permits assembly of the top plate with the guideway andalso accommodates a leaf-type spring clip I2T,

the body portion of which is pressed fiatwise against the top plateII8-by tongues I28, bent upwardly from the clip, which yieldingly engagethe overhanging ledges I2 6 on the carrier. Other bottoms of slots I30opening to the front edge of one side plate and to the rear edge of theother side plate, and that there is sufficient v clearance between theplungers of the bridging oontactor and the guideway H I to permithooking of the tangs H5 of the plungers over their respective shouldersH6 in assembling the contactor with the carrier.

The stationary contacts I01, I68 and I69 have concave faces so that themovable contacts 94,

and 96 engage them with a detent action to define the off position ofthe master switch,

Attention is also directed to the fact that the terminal heads I8 areprovided with recesses- I3I aligning with the opposite ends of thebridging oontactor III in the off switch and into which the plungers ofthe bridging oontactor snap to increase the positiveness of the detentaction at the off position of the switch.

While the detent-like engagement of the plungers H2 of the bridgingoontactor with their cooperating stationary contacts H6 defines the onposition of the switch, it is desirable to provide at least two recessesI32 in the terminal heads 18 into which each pair of movable contacts 94and 96 are projected by their springs 98 in the on position of theswitch to further guard against accidental actuation 'from saidposition. It is to be observed that the provision of groundingconnectors for the movable contact members 9I permits the lever 21 to bemade of insulating material if desired, but the lever is preferably madeas a one-piece die casting. If the lever 21 is formed of insulatingmaterial,

the insulating guideway for the bridging contactor I I I can bedispensed with and the plungers guided by the hole in the lever itself.

From the foregoing description it will be readily seen that thisinvention provides an improved electrical control instrumentality of thetype adapted to be used as an aircraft master switch which isofunusually compact and simple construction and which will prove sturdyand dependable in service.

What I claim as my invention is:

1. In a switch of the character described: spaced apart substantiallyparallel metallic supports adapted to be connected to ground; a leverhaving a hub substantially medially of its ends pivotally receivedbetween said supports, said lever having a hole in one arm thereof theaxis of which is parallel to the contact members at each side of said'arm in a plane normal to the pivot axis of the lever and overlying thehole therein; a compression spring in said hole confined between thecontact mempivot axis of the lever;

bers to yieldingly urge the same apart and outwardly from the adjacentfaces of said arm;

position of the means passing through said hole andengaging the contactmembers to limit spreading apart-thereof; a grounding connector for eachcontact member having a part confined between its adjacent contactmember and the spring and having another part confined between one faceof the hub and the metallic support adjacent thereto; and spring meansreacting between the hub of the lever and one of said connectors forholding both connec tors in engagement with said metallic supports.

2. In a switch of the character described: a switch housing having ametal wall portion adapted to be connected to ground; a lever substantially medially pivoted from the housing with one-arm thereofinsidethe housing and theother arm thereof projecting outside thehousing to provide an actuator for the lever; a movable contact carried'by the lever arm inside the housing alongside one face thereof forswinging motion therewith about the pivot axis of the'lever and forlimited motion relative thereto in a direction substantially parallel tosaid pivot axis; a stationary contact on the housing insulated therefromand located so as to be engaged by the movable contact in one positionof the lever; means biasing the movable contact outwardly away from itslever arm so that said contacts engage with substantial pressure in saidposition of the lever; a resilient metal grounding connector for themovable contact having a part maintained in electrical engagementtherewith by said biasing means and having a portion disposed alongsidesaid metal wall portion of the housing; and spring means confinedbetween the lever and said portion of the connector to yieldingly pressthe same into engagement with said metal wall portion of the housing tothereby effectively ground the movable contact.

8. In a switch of the character described: a movable contact carrierhaving spaced holes therein the axes of which are normal to the plane ofmotion of the carrier; a pair of movable contacts projecting into one ofsaid holes from opposite sides of the carrier; a compression springdisposed in said. hole between the contacts to yieldingly urge the sameapart; an insuiating guideway fixed tothe carrier and surrounding saidcontacts to guide the same for motion to- Ward and from each other insaid hole; coopcrating abutments on the contacts and the guideway forlimiting motion thereof apart and for holding the contacts assembledwith .the carrie'r; other contact members overlying opposite sides ofthe carrier adjacent to the hole therein; a compression spring in saidother hole confined between the contact members to yieldingly urge thesame apart; and means-passing through said other hole and engaging saidother contact members to limit spreading apart thereof and to therebyhold the same assembled with the carmen 4. In an electrical switchinstrumentality of the type having a housing: a metal contact car rieradapted to be mounted for pivotal motion on an axis fixed with respectto the housing, said carrier having spaced holes therein the axes ofwhich are substantially parallel to the pivot axis of the carrier; apair of movable contacts projecting into one of said holes from oppositesides of the carrier; a compression spring disposed in said hole betweenthe contacts to yieldingly urge the same apart; an insulating guidewayfixed to the carrier and surrounding said contacts to insulate the samefrom the carrier and to guide the contacts for axial motion toward andfrom each other in said hole; cooperating abutments on said contacts andthe guideway for limitingmation'of the contacts apart and for holdingthe contacts assembled with the carrier; other contact members :at eachside of the carrier ioverlying the other hole therein; a compression:

spring in said other hole for'yieldingly urging} end of said compressionspring and the contact:

member adjacent thereto soas tobe held in good electrical contacttherewith; and having another portion disposed alongside one .faceofthe. carrier adjacent to its pivot axis sooas. to be engageable with agrounded part of the switch housing alongside the carrier; andspring'means confined between the carrier and said lportionrof oneoflthe grounded housing parts for yieldingly urging the same outwardlyaway from the carrier.

5 In a switch of the type having a housing provided with spaced apartmetal wall portions-- adapted to be connected to ground and stationanycontacts insulated from saidv metal Wall portions: a lever pivotallysupported. from .said

spaced metal wall portions. at a medial pointaoi the lever and with onearm disposed inside the housing to provide a contact carrier; a ,pairof; contacts, one on each side ofthc carrier, bodily movable with thecarrier; compression spring means reacting against the contacts to'y-iclda ingly urge the same into engagementwith said stationarycontacts on the housing in one posi tion of the carrier; means forelectrically connecting said movable contacts; other contact.

members bodily movable with, the carrier andv overlying opposite facesof the carrier; compression spring means for yieldinglyv forcing saidother contact members into engagement with cooperating stationarycontacts on the housing in u another position of the carrier; agroundingv com nector for each of said other contact members,

each of said grounding connectors having an apertured end portionconfined between the.

spring means and one of said other contact members and having anextension engaged with the metal wall portions of the housing adjacentthereto; and spring means reacting between one of said groundingconnector extensions and the lever for simultaneously pressing each ofsaid grounding connector extensions into good :elec'-'- trical contactwith said metal wall portions of the housing.

6. In a switch of the character described: two

insulating plates constituting a pair .of terminal heads; a metal walldisposed edgewise between said terminal heads and secured thereto to,hold the same in parallel spaced apart relationship, said metal wallcooperating with the terminal,

heads to provide a switch housing and being adapted to be connected toground; spaced apart ap-ertured ears on said metal wall overlying theopposing faces of the terminal heads inside the housing; a switch leversubstantially medially pivotally mounted between said terminal heads andhaving a portion inside the housing adapted to swing in a plane parallelto the terminal heads; contact members at each side of said leverportion constrained to motion therewith; spring means reacting againstsaid contact members to yieldingly urge the same toward the inner facesof the terminal heads for engagement with cooperating stationarycontacts on the terminal heads in one position of the lever; and meanselectrically connected with each of said contact members and with itsadjacent apertured ear whereby engagement of the contact members withsaid stationary contacts provides a ground connection for saidstationary contacts.

7. Ina switch of the type having aligned spaced apart stationarycontacts: a metal contact carrier movable between said stationarycontacts, said carrier having a hole therein; a bridging contactordisposed in said hole so as to be bodily movable with the carrier, saidbridging contactor having portions projecting from opposite sides of thecarrier for engagement with the stationary contacts'in one position ofthe carrier; and an insulating shell surrounding the bridging contactor,said shell comprising a plurality of interlocked separate insulatingplates encircling the edges of said hole to preclude engagement of thebridging contactor with the carrier; and means on certain of saidinsulating plates engaged with portions of the carrier bounding saidhole therein for precluding axial disassembling motion of the shellrelative to the hole in the carrier. 7

8. In a switch of the type having aligned spaced apart stationarycontacts: a contact carrier movable between said stationary contacts,

said carrier having a hole therein; a bridging contactor disposed insaid hole so as to be bodily movable with the carrier, said bridgingcontactor comprising a pairof opposed electrically connected plungersaxially movable in said hole and having contact portions projecting fromopposite sides of the carrier for engagement with the stationarycontacts in one position of the carrier; a spring confined between theplungers for yieldingly forcing the same apart; an insulating shell insaid hole surrounding the plungers to guide the same for axial motion insaid hole, said shell comprising a plurality of interlocked separateinsulating plates encircling the edges of said hole; means on at leastone of said insulating plates engaging portions of the carrier boundingthe hole therein for precluding axial disassembling motion of the shellrelativeto the hole in the carrier; and cooperating means on the shelland the plungers for limiting axial motion of the plungers apart underthe influence of thespring confined therebetween.

9. In a switch of the type having aligned spaced apart stationarycontacts: a contact carrier movable between said stationary contacts,said carrier having a hole therein; a bridging contactor disposed insaid hole so as to be bodily movable with the carrier, said bridgingcontactor comprising a pair of opposed hollow plungers substantiallyrectangular in cross section, said plungers being axially movable insaid hole and having contact portions projecting from opposite sides ofthe carrier for engagement with the stationary contacts in one positionof the carrier; a compression spring having its ends telescoped into thehollow interiors of the plungers for yieldingly forcing the same apart;a jumper of flexible low resistance wire inside the bridging contactorhaving portions confined between the ends of the spring and the innersides of said contact engaging portions of the plungers to electricallyconnect the same independently of the spring; an insulating shell insaid hole comprising two substantially opposite pairs of insulatingplates having interlocking connections with each other to form aguideway substantially rectangular in cross section to receive theplungers and to guide the same for axial motion; means on at least oneof said plates engaging portions of the carrier bounding the holetherein for precluding axial disassembling motion of the guidewayrelative to said hole; and cooperating abutments on the plungers and twoof the plates engageable to limit axial motion of the plungers apartunder the influence of the spring confined ther'ebetween.

10. In a switch of the type having aligned spaced apart stationarycontacts: a metal contact carrier movable between said stationarycontacts, said carrier having a hole thereinopening to one marginal edgeof the carrier through a restricted throat; a plurality of insulatingplates lining the edges of said hole and forming a hollow insulatingguideway axially of said hole, one

of said plates extending across said throat at its junction with thehole; means connecting the plates togethensaid means being operable tohold the plates against relative shifting edgewise or toward one anotherwhereby said connecting means cooperates with the edge portionsof thehole to hold the guideway against motion relative to the carrier exceptin a direction axially of the hole in the carrier; means on at least oneof the plates engaging portions at opposite sides of the carrier.bounding the hole therein for precluding axial disassembling motion ofthe guideway relag tive to said hole; a bridging contactor comprisinggoopposite electrically connected contact sections telescoped into theinsulating guideway from opposite sides of the carrier; a springconfined between said contact sections to yieldingly urge the same apartand into firm engagement with. the

stationary-contact in one position of the carrier;

and cooperating abutments on the telescoping contact sections'an'd theguideway for limiting spreading of said sections apart whereby thebridging contactor may be assembled as a unit 40 with the carrier priorto assembly of the carrier in the switch. l

11. In a switch of the character described: a

pair of terminal heads in'fixed spaced apart relationship parallel toand opposing one another; a

lever pivotally secured between.said terminal heads for motion in aplane parallel to them,

with one arm of said lever extending beyond said terminalheads to forman actuator for the switch and the other arm of said leverlying betweensaid terminal heads and forming a contact carrier; a pair of contactorspiders each positioned between one side of said carrier and theterminal head adjacent thereto and adapted to be carried by said carrierand to engage fixed contacts on the terminal head in one position of thecarrier; lug means on the carrier cooperating with said contactorspiders to constrain them to move with the carrier in the plane ofcarrier motion but leav- 7 ing themlfree to move toward and from theterminal' head; and means yieldingly biasing each of said contactorspiders away from the adjacent side of the carrier and into engagementwith the adjacent terminal head. it 12. In a switch of the characterdescribed: a pair of terminal heads; means holding said terminal headsin spaced apart relationship parallel to and'opposing one another, saidmeans cooperatingiwith the terminal heads to define a switch housingopen at one side; a lever pivoted substantially medially between saidterminal heads for motion in a plane parallel to them, one end of saidlever extending out of said housing through its open side to provide anactuator for thelswitch and the other end thereof lying within theoilsing and forming a carrier; a contactor spider-positioned: between.each side of. the carrier and its adjacent terminal head and adapted tobe moved by the carrier and toengage fixed contacts on the terminal headin one position of the carrier'glug means-on the carrier cooperatingwith each of said contactor spiders to constrain the spiders to:movement withthe carrier in. the plane ofvits motion but leaving'themfree to move in directions parallel to the lever axis; and spring meansyieldingly urging each of the spiders into engagement with its adjacentterminal head.

13. In aswit'ch of" the character described: a pair of terminal heads infixed spaced apart relationship parallel to and opposing one an-- other;a lever pivotally secured between said terminal heads for motion in aplane parallel to them, with one" arm ofsaid lever extending beyond saidterminal headsto form an actuator for the switch and the other arm ofsaid lever- 'lyingbetween said terminal heads and forming a contactcarrier; a pair of contactor spiders each positioned between one side ofsaid carrier and the terminal head adjacent thereto and adapted to becarried by said carrier and to engage fixed contacts on the terminalhead in'one' position of the carrier; means cooperating with saidcontactor spidersto constrain them to move with the carrier in the planeof carrier 1 motion but leaving them free to move toward and fromvtheterminal head; and means yieldihgly biasing each of said. contactor"spiders into engagement with its adjacent terminal head.

14. In a switch of the character described: a pair of terminal headsfixed in spaced apart relationship; a lever journaled on a pivot fixedwith respectto said terminal heads, one arm of said lever extendingoutwardly of the terminal heads to provide an actuator for the switch,

and the other arm forming a carrier'movablein a plane parallel'to andintermediate the terminal heads, said carrier having a holetherethrough,

'the' axis of which is substantially" parallel to the lever pivot axis;a pair of" electrically connected telescoping contactor members in saidhole, each extending outwardly therefrom, and adapted to engage a fixedcontact on one 01" the terminal headsin'one position of: the carrier;and a spring between said contactor members urging them apart and intoengagement with said fixed contacts in said position of the? carrier: sothat electric current may beconducted from. the" fixed contact on oneterminal head throughtheicontactor members tothe' fixed. contact on: theother terminal head.

15. Anlaircraft master'switch ofithe character described comprising: apair of terminal heads fixed inzspacedapart; parallel and opposedrelationship;: a lever pivotally secured betweenv said terminal headsfor motion in auplane parallel to them to either of two positions, onearm of said lever extending beyond the terminal heads to form anactuator for the. switch, and theother arm of said lever lying between.said terminal heads and forming a contact carrier, said contact carrierhaving a" hole therethrough the axis of which is parallel to the-pivotaxis of: thel'ever; a pair of contactor: spiders each positioned.between one side of said carrier and: the terminal head adjacent theretosaid contactor spiders being adapted to be carried by said carrier andto engage fixed contacts on the terminal head in one position of thecarrier to thereby connect said contacts with ground; lugs on thecarrier cooperating with said contactor spiders to constrain them tomove with the carrier in the plane of carrier motion but leaving themfree to move toward and from the terminal head; means yieldingly biasingeach of said contactor spiders into engagement with its adjacentterminal head; a pair of electrically connected adapted to engage astationary contact on the terminal head adjacent thereto in the otherposition of the carrier to completea battery circuit across saidstationary contacts; and a springbetween said contactor members urgingthem apart and toward engagement with the terminal heads.

EDWARD N. JACOBI.

REFERENCES CITED The following, references are of record in the file ofthis patent: v

UNITED STATES. PATENTS Name Date Peterson Jan. 10, 1933 Peterson Jan.10, 1933

